1. Field of the Invention
The present invention relates to an insert-indexable tool used for grooving, cutting-off, or the like of an object to be machined.
2. Description of Related Art
As an insert-indexable tool used for a grooving operation or a cutting-off operation, an insert-indexable tool is known in which a pair of jaws are formed in an elastically deformable manner at a distal portion of a holder, an insert mount seat is formed by configuring a clamping face provided on one of the pair of jaws and a base face provided on the other of the pair of jaws so as to face each other, the clamping face and the base face are arranged so as to face each other, and an insert having a cutting edge is clamped in the insert mount seat.
An insert-indexable tool, in which an insert mount seat is included in a head member that is detachably attached to a distal portion of a holder, has been proposed in Published Japanese Patent No. 2902085.
In the insert-indexable tool disclosed in the above patent document, the head member configured in a flat plate shape is fixed to a side face of the holder at the distal end thereof, and a clamping screw having a pressing portion to elastically move one of a pair of jaws in a clamping direction is provided.
The holder is provided with a threaded hole into which the clamping screw is screwed, and one of the pair of jaws of the head member is provided with a spot facing. The threaded hole and the spot facing have a common axis, and the common axis is oriented so as to be inclined with respect to intersecting axes of a front face and the side faces of the holder, i.e., so as to be inclined with respect to the clamping direction of the insert mount seat.
In the insert-indexable tool, the insert is clamped by screwing the clamping screw so as to fix the head member while being drawn toward the holder, and by pressing the spot facing by the pressing portion of the clamping screw to elastically move one of the pair of jaws in the clamping direction.
However, in the insert-indexable tool disclosed in the above patent document, because the threaded hole and the spot facing have the common axis, i.e., the axis of the threaded hole and the center axis of the spot facing are configured so as to coincide, the axis of the clamping screw coincides with the center axis of the spot facing when the clamping screw is screwed into the threaded hole; therefore, the contact position between the pressing portion of the clamping screw and spot facing may vary depending on the alignment of the insert, tightening method for the clamping screw, or the like.
For example, when the pressing portion of the clamping screw and spot facing contact at a position near the proximal end portion of the insert mount seat, i.e., at a position remote from the insert, the force of clamping the insert may be less, and a problem may be encountered in that the insert is not firmly fixed.
Moreover, when the pressing portion of the clamping screw and spot facing contact at a position at which a tangential vector of the tightening rotational operation for the clamping screw is oriented away from the holder, one of the pair of jaws may deform so as to be away from the holder when the clamping screw is tightened, and the insert to be clamed may be misaligned.
As stated above, due to the variation in the contact position between the pressing portion of the clamping screw and spot facing, problems are encountered in that the insert is not firmly fixed.